Chinese warlord with ties to the Nationalist Party. Born into a wealthy family in Wutai (Wut'ai), Shanxi (Shansi) Province, China, on 8 October 1883, Yan Xisgan (Yen Hsi-shan) attended the military college of his native province between 1901 and 1904 and then went to Japan on a government scholarship. He graduated from the prestigious Shikan Gakko (military academy) in 1909. Returning to Shanxi after his graduation, Yan rose to the rank of colonel and regimental commander by 1910.

On the outbreak of the October 1911 Revolution, Yan joined the revolutionaries and was appointed military governor of Shanxi. By 1917, he was the sole ruler of the province. During the turbulent decade that followed, Yan proved adroit at navigating among the various warlord coalitions that were constantly battling for control of China. At the same time, his social and economic reforms turned Shanxi into a model province that contrasted sharply with the depredations of other warlords. In 1927, Yan joined the Nationalists, led by Jiang Jieshi (Chiang Kai-shek). After the Nationalist reunification of China the following year, Jiang rewarded Yan by confirming him as governor of Shanxi.

In the 1930s, Yan's position was threatened by pressure from the Japanese, who seized Manchuria in 1931, and from the Chinese Communists, who had relocated to the city of Yan'an (Yenan) in Shanxi Province. Yan responded by implementing a massive economic reform program in 1934 and by strengthening his ties to the Nationalists, but he had little success because of his inadequate financial resources and his history of isolation. Within a few months of the outbreak of the Sino-Japanese War in July 1937, Yan's army was barely maintaining a foothold in Shanxi. His relations with the Communists were poor. Following an open clash with them in 1939, Yan attempted to establish connections with the Japanese, prompting accusations of treason.

After the Japanese surrender in 1945, Yan continued to resist the advance of the Communists in northern China, but his efforts, including the use of Japanese troops, ultimately failed. Forced from Shanxi in April 1949, he fled to Taiwan. He died in Taibei on 24 May 1960.